Shareholdings
| Concept | 2022-10-01 to 2023-09-30 | As at 2023-09-30 | As at 2022-09-30 | 
|---|---|---|---|
| Shareholdings | |||
| Reporting company | |||
| Investment shares held for pure investment | |||
| Shares not listed | |||
| Number of issues | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Carrying amount | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total of dividends received | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total of gain (loss) on sale | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total of valuation gain (loss) | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Shares other than those not listed | |||
| Number of issues | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Carrying amount | — | 
                                                204,895,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                148,565,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total of dividends received | 
                                                5,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total of gain (loss) on sale | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total of valuation gain (loss) | 
                                                107,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |